Enable ExecShield Protection Against Buffer Overflows

Open your /etc/sysctl.conf file:

# vi /etc/sysctl.conf

Add the following lines:

kernel.exec-shield = 1

kernel.randomize_va_space = 1

Save and close the file. First line will enable ExecShield protection and second line will enable random placement of virtual memory regions protection. To load in sysctl settings, enter:

# sysctl -p

reference: http://www.cyberciti.biz/faq/what-is-rhel-centos-fedora-core-execshield/